"And that's removing 1.2 billion pounds of carbon annually from customer electricity use, and that is equivalent to 150,000 cars taken off our streets," said Jeannie Bruins, a Los Altos Council Member.

Silicon Valley Clean Energy is a joint venture of 11 cities plus the County of Santa Clara.

It becomes the power source for 68,000 customers Monday and 180,000 more in July.

By design, they're automatically switched to the new utility, unless they opt-out.

Advocates say that was the only way Silicon Valley Clean Energy could negotiate favorable contracts to buy solar, wind, geothermal and hydro-generated power.

"If it had been an opt-in process, there wouldn't have been any certainty as to what kind of commitment to make, so I think that opt-out is absolutely critical to the success of community choice," said Bruce Karney, with Carbon Free Silicon Valley.

Sample rates have been comparable to PG&E. If you select the 50 percent renewable energy plan, you'd pay $98.19 or $102.07 if you select the 100 percent renewable energy plan. PG&E'S rate is $98.67 but its sourcing is 30 percent renewable and 60 percent carbon-free.

PG&E will continue to deliver the power and handle billing and repairs.